1. Field of the Invention
The present invention relates to a method of and apparatus for capturing images, and more particularly, to a method of and apparatus for capturing images, in which an initialization process is executed by a processor as a background operation and the apparatus is immediately operated using an internal memory.
2. Description of the Related Art
Recently, digital still cameras (DSCs) have become popular, supplanting conventional film cameras. In addition to single lens reflex (SLR) cameras for professionals, cameras for other types of users are being manufactured. Specifically, ultra-compact cameras that are easy to carry and can quickly capture images when needed are becoming popular with users due to their stylish designs, high performance, and small size.
Digital cameras use memory chips instead of film to capture images, and may control the number of capturable images or give different intensity to pictures. In addition, the digital cameras display images by generating electrical signals according to the brightness of the scene via a charged coupled device (CCD), and control analog digital converter (ADC) chipsets or JPEG chipsets via a central processing unit (CPU) chipset.
The JPEG chipset compresses digital signals converted in the ADC chipset that receives data from the CCD, and stores them in .jpg file in an external memory. JPG is a standard compression technique for efficiently adjusting the size of the image file while maintaining nearly the same picture quality as the original. The image processed in the JPEG chipset is 2 to 4 MB, and is stored in a flash memory.
The digital cameras have information on the date the image was captured, an index, and data for a monitor in JPEG-image data. The exchangeable image file (Exif), digital print order format (DPOF), PictBridge, camera image file format (CIFF), and design rule for camera file system (DCF) are file formats used by most digital cameras. DPOF stores image output information in a memory card MISC folder, selects images that will be output using the information, and determines the number of copies of the images.
Generally, DCF contains information on the structure of a directory, the name of a file, the structure of the file, thumbnails, and screen nail images. In addition, when determining the name of an image data (file), DCF reads information on images stored in an external memory before storing it therein, and names the file afterwards.
In order to record captured images, the digital cameras use an external memory such as a multimedia card (MMC), a smart media (SM) card, a compact flash (CF), or a memory stick.
When a user turns the power on, the digital camera reads management information of the external memory, which stores information on available memory, determines whether there is enough memory to capture more images, and computes the number of images the digital camera can capture according to the available memory.
In addition, the read management information is recorded in a memory, e.g., a main CPU cache or a main CPU memory in the digital camera.
FIG. 1 is a flow chart illustrating the initialization process of a conventional digital camera.
When a system is booted, a digital camera executes an initialization.
First, a CPU memory, (e.g., SRAM), a universal asynchronous receiver transmitter (UART), and a flash are initialized S11.
Then, a CCD, an image-processing unit, and digital camera hardware are initialized S21, S31, S41. For example, an image-processing DSP, a motor, a video bus, a USD device, an LCD, and a button are initialized. The initialization processes may be performed during the initialization of an OS or in a different order depending on the system, and the OS may initialize hardware.
Once the basic initialization process of the system has been completed, an external memory (e.g., a memory card) is initialized in order to store captured image data S51.
The initialization of the external memory will be described in detail with reference to FIG. 2.
Once the initialization process of the external memory has been completed, an image is captured, DCF information (list) is renewed, and the captured image is stored in the external memory S61 and S71. Generally, the DCF format contains information on the structure of a directory, the name and structure of a file, thumbnails, and screen nail images. In addition, when determining the name of an image file, the DCF reads information on images stored an external memory before storing it therein, and names file afterwards. The aforementioned steps may be sequentially or concurrently executed. In some cases, the process may be executed in a different order.
FIG. 2 is a flow chart illustrating the initialization process of the external memory in FIG. 1.
First, the initialization process is initiated, and the mounting process is carried out in order to access to a file system of an external memory S53.
In addition, available memory space and the number of images that can be captured are determined S55.
Next, when storing captured image data, information on existing image data, which is stored in the external memory, is read in order to name the file S57. Here, “DCF” may be used as a part of the filename, and the file (image data) may be managed using DCF information.
Then, the file is named via the read information, and the DCF information is renewed. The aforementioned steps may be sequentially or concurrently executed. In some cases, the process may be executed in a different order.
A digital camera should take the least amount of time to boot so that a user can capture images quickly. However, as described with reference to FIGS. 1 and 2, the initialization process requires a significant amount of time, and thus hinders immediate use of the camera.
Japanese Unexamined Patent Application No. 2001-128107 discloses a digital camera that stores captured data (image data) in a temporary memory, determines whether a removable recording medium (e.g., a memory card) can be used, and records the captured data in the temporary memory of the removable recording medium.
However, the invention does not disclose information on steps the camera executes to determine whether the removable recording medium can be used while storing the captured data in the memory, and the aforementioned steps have a significant impact on the initialization of the system. Accordingly, a solution to the aforementioned problems is required.
In addition, even though the initialization is executed in a basic system and an image-processing device, a time lag still exists in initializing an external memory, mounting files, or renewing DCF information, resulting in degradation of system initialization, which is a problem.